The present invention generally relates to a process for printing identification cards such as driver""s licenses and credit cards. Particularly, the invention involves using a thermal transfer printing process to produce a metallic security outline around selected indicia printed on the card. The invention also encompasses identification cards produced by this process.
In recent years, various agencies have issued more identification cards such as passports, visas, driver""s licenses, credit cards, bank cards, security access cards, and the like. Along with the increased circulation of valid identification cards, there has been an increase in card tampering and forgery. These counterfeiting activities are sophisticated and it has become more difficult to detect falsified cards. The industry has attempted to address this problem by manufacturing new tamper-resistant cards in a number of ways.
For example, Chatwin et al., U.S. Pat. No. 5,492,370 discloses a method for making security articles such as passports, visas, vehicle license certificates, vehicle tax certificates, identity cards, and the like. The article comprises a plastic substrate having embossed sections that provide a holographic effect. A thin metallic coating is applied over the entire surface of the substrate. An indicia-receptive coating is then applied over the non-embossed sections of the substrate so that at least part of the holographic effect remains visible. The coating is printed with security indicia. A protective transparent lacquer then may be coated on the surface of the article.
Dell""olmo, U.S. Pat. No. 5,873,305 discloses a method for protecting pre-printed sheets of paper (for example, leaflets, stock certificates and bank notes) by impressing microengravings on all or some of the printed portions of the paper. The microengravings correspond to holograms or diffraction patterns and are produced by a hot embossing process. The microengravings remain permanently retained on the pre-printed portion of the document after the document has been cooled.
Kaule et al., U.S. Pat. No. 5,820,971 discloses a method for making a multi-layer identification card having a security element. A transfer embossing foil can be used to produce the security element. The transfer embossing foil comprises a carrier material having an embossed layer that is coated with a metallized reflective layer. The card substrate is coated with a reaction adhesive, and the embossed structure and metal layer are transferred and bonded to the substrate by this adhesive.
Other card-issuing agencies apply a transparent coating over the entire surface of the card to deter forgery and assist in detecting counterfeit cards. For example, identification cards are often printed using a thermal transfer dye-sublimation process. Three printing passes are used to apply three colored dyes, yellow, magenta, and cyan, in a specific pattern and print information on the surface of the card. A fourth pass applies a transparent coating that overlays the entire surface of the card. This clear outer coating is a protective coating that helps deter tampering with the printed information on the card. The coating provides the card with a durable and scratch-resistant finish. A security watermark can be applied on the protective coating in a random or predetermined pattern. For example, a state agency may issue a driver""s license with the name of the state printed in a repeating pattern on the clear protective coating in such a manner that the printed information beneath the protective coating remains visible.
Although the foregoing systems may be somewhat effective in manufacturing tamper-resistant identification cards, there is a need for an improved system. It would be desirable to have a process that does not require complex multiple steps or special processing such as the holographic embossing of a material""s surface. There is a need for a relatively simple process that a card-issuing agency can use at the time and place where the card is issued. The present invention provides such a process. The invention also encompasses the identification cards produced by the process.
The present invention relates to a process for thermal transfer printing an identification card to produce a metallic foil security feature on the card. The process comprises the steps of: a) providing a card substrate having a thermal transfer dye-receptive surface; b) providing a set thermal dye transfer panels including a metallic foil panel; c) printing indicia onto the dye-receptive surface; and d) printing a metallic border along the outside edges of selected printed indicia to form a metallic security outline around the selected indicia.
The metallic security outline is produced with such fine resolution around the selected feature that potential counterfeit printers would have a difficult time reproducing the feature with conventional thermal printing equipment.
The card substrate may be in the form of a sheet, film, continuous web, individual card or other material suitable for continuous printing processes. Suitable substrate materials include, for example, polyesters, vinyls, polyamides, polyolefins, polyacrylates, polyimides, polystyrenes, polysulfones, aramids, polycarbonates, and celluloses. The card substrate may be coated with a dye-receptive coating comprising a polymer selected from the group consisting of polyesters, vinyls, polyamides, polyolefins, polyacrylates, polyimides, polystyrenes, polycarbonates, celluloses, and mixtures thereof.
The indicia may be printed in a monochrome format for black and white images or text, or alternatively may be printed in a process color format for color images. The metallic foil transfer panel has been known in the art, and is sequenced within the thermal dye transfer media for sequential printing. A transparent, protective coating may be applied over the printed surface of the card to make the card durable and scratch-resistant.
This invention also encompasses identification cards produced by the above-described processes. For example, licenses and credit cards having selected printed indicia with a metallic border may be produced by this process.
It is noted that the preferred embodiment takes advantage of selective registration of the metallic foil so that only a selected portion of the indicia is provided with the metallic foil outline. This selected printing feature is important because it requires a highly accurate and expensive print engine to accurately align the pixels to achieve the desired effect without ghosting and fuzzy edge artifacts. While multiple pass thermal printing devices are available on the market, most available devices do not have the same accuracy of registration as would a specialized commercial identification card printer as contemplated in the invention. Printers having substrate transport mechanisms with this type of accuracy are very expensive and usually only available to card issuing authorities through specific vendors. Accordingly, the highly accurate placement of the metallic foil border is readily identifiable and serves as an inexpensive security feature. Lesser accurate thermal printing devices will tend to leave sloppy edges which readily detectible to someone familiar with the security feature.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.